Suction blast gun



Aug. 26, 1952 R. R..GARVER SUCTION BLAST GUN Filed Aug. 29, 1950 INVENTOR m Y v w R R C T H 0 6 M w. M m

Patented Aug. 26, 1952 SUCTION BLAST GUN Ralph E. Garver, Hagersto'wn, Md., assignor to Pangborn Corporation, Hagerstown, Md., a corporation of Maryland Application August 29, 1950, Serial No. 182,023 1 Among the objects of the present invention is' the provision of a particle blastinggun of highly efllcient, simple and compact construction.

Additional objects of the present invention iiielude particle-blasting guns that can be used to enter small openings and cavities the internalsurfaces of which are to be subjected to the blasting treatment, and that can be used with wet or dry abrasive.

The above as well as other objects of the present invention will be more readily understood from the following description of several of its exempliflcations, taken in conjunction with the appended drawings wherein:

Fig. 1 shows a vertical cross-section of a particle blasting gun in accordance with one embodiment of this invention;

Fig. 2 is a sectional view along 2-2 of Fig. 1;

Fig. 3 is a plan view of the blasting gun shown in Figs. 1 and 2; and

Fig. 4 is a view similar to Fig. 2 of a modified form of blasting gun exemplifying the present invention.

The gun of Figs. 1, 2 and 3 comprises two substantially parallel lines I and 2 for supplying abrasive and air respectively. ,The lines are shown as of yieldable material such as rubberized fabric and are connected to a nozzle holder or gun body 4.

In this embodiment of the invention, the gun body 4 is an integral iron casting provided as by drilling with separate air and abrasive receiving passages 5 and 6 respectively, that are substantially parallel to each other. The passages 5 and 6 are interconnected by a perpendicular air jet orifice 1. Aligned with the jet orifice is an external opening that extends into the abrasive receiving passageway 6 and receives a nozzle 9. Nozzle 9 extends into the passageway 6 and is retained in place by means of set screw l threadedly received in the outer wall of the gun body which is suitably cut away as shown. for convenience. The distance between the innermost end of the nozzle 9 and the outer tip of orifice 1 may vary from about 4 inch to about 1 inch or more as desired.

Abrasive line I is received within an enlarged outer portion of passageway 6 and retained in place by means of one or more flat-head wood' screws l6 that extend through openings in the surrounding wall portion I and engage the wall 1 Claim. (01. 5111) of line I Where more than one screw 16 is used they are staggered vertically along as well as peripherally around the line. The oppositeend of passageway 6 is closed as by the threadedly flttedplugZl." j

Line 2, a hose similar to line l,'is connected to, air receiving passageway 5 by means of nipple l9 which threadedly engages the corresponding end of passageway 5, and'around which the line is held as by means of hose clamp 20. A second plug 22 is shown as closing oil the opposite end of this passageway. Both plugs -may be removed for facilitating the cleaning of the gun body 4.

To simplify the manipulation of the gun, as when it is to be inserted into pipes to blast their internal surfaces, the projecting body portion I5 is shaped to form a reduced skirt over which a rigid tube such as a pipe 3 is received and held as by set screws I I, I2 threadedly engaged in the pipe walls and jammed against the skirt. For

improving this anchorage, the pipe is reenforced at the threaded set screwsites by lugs l3, H which may be welded in place and are also threadedly engaged by the set screws.

Fig. 4 shows a modified form of construction which differs from that of Figs. 1, 2 and 3 in that the nozzle is completely v recessed into the gun body, and the mounting pipe and set screw lugs are dimensioned so asto lie entirely within the outlines of the body periphery.

It has been found that abrasive blasting is a. simple and extremely effective treatment by which machined surfaces such as pump cylinders, cylinder bores of piston-type internal combustion engines, or the like can be given a fine finish that is much superior to the conventional honing.

Not only does the blasting remove or deemphasize machining or tool marks, but it gives the blasted surface a very fine irregularity or grained appearance that compares favorably with the etched-type surface heretofore used to improve lubrication of the above cylinders. The blasting is easier and less expensive to efiect than the etching even without the honing normally used as a preparatory treatment for the etching.

A feature of the present invention is the compactness of the assembly. The nozzle is practically entirely Within the gun body, yet is readily replaceable. The air jet passageway is an integral part of the gun body but is not subjected to any serious amounts of erosion and does not have to be replaced. The entire gun can be made in varying sizes, the smallest having an overall diameter of about two inches.

The perpendicularity between the blasting direction and the supply lines is of special significance inasmuch as this is highly advantageous when blasting the inner surfaces of hollow articles. If desired however the nozzle 9 and air jet 1 can be tilted from the perpendicular in a direction toward the plugs, by amounts of up to about 30 degrees. This improves the blasting of surfaces into which the cannot be completely inserted. As an alternative construction the plugs, 2|, 22 may be replaced by imperforate portions of the body so that the passages 5, 6 have blind lower ends.

A highly satisfactory blasting technique employs an abrasive slurry of {it} to 35,9. mesh-sand in water, and an air pressure or 30 per: square inch, with the nozzle 9 having a blasting opening inch in diameter, The same sand can also be efiectively used in dry condition, although for graining purposes the wet blasting is generally superior. Metal particles can also be used in p ace 9 t e san and the o-ca l d se t" a as es su h. as finely divided tern hush-s or walnut she ls a al o su ed o us with can eli the n e t on a As many apparently widely different embodi= meats cl hi i n n may be m e. withou departing rom the spi i and. s o e he eqf it is e be. understoed h t. this in en on i o imited n the sneelfle embodimen i ree except as de: ned lathe. appe ed elai n-v 7 What sel imlceq is: I

a eemp e lasting gun let qieeting a 4 stream of abrasive particles, an elongated integral gun body having two parallel side-by-side passages both extending through its entire length, removable plugs closing ofi one end of each passage, separate securing elements separately provided at the unplugged ends of the passages to separately receive independent conduits, one for a supply oi abrasive particles and the-other for a supply of impelling fluid, a discharge nozzle projecting out through a wall of one of the passages for the lateral discharge of the blasting mixture from the gun body, the body wall between the passages including an intercommunication duct ali ned with the male for jettin the supplie fluid from the other passage out through the nozzle, said nozzle having its inner end located about 4,4,," to; about 1" iron; the near end of the duct to cause the jetted fluid to eject a stream of abrasive particles from the other passageway and through the nozzle.

Number 1 Name. Date 2, 92,89 Jan 1 1946 angles 

